Diagnosis, treatment, and management of rickets: a position statement from the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology

Rickets results from impaired mineralization of growing bone due to alterations in calcium and phosphate homeostasis. Clinical signs of rickets are related to the age of the patient, the duration of the disease, and the underlying disorder. The most common signs of rickets are swelling of the wrists, knees or ankles, bowing of the legs (knock-knees, outward bowing, or both) and inability to walk. However, clinical features alone cannot differentiate between the various forms of rickets. Rickets includes a heterogeneous group of acquired and inherited diseases. Nutritional rickets is due to a deficiency of vitamin D, dietary calcium or phosphate. Mutations in genes responsible for vitamin D metabolism or function, the production or breakdown of fibroblast growth factor 23, renal phosphate regulation, or bone mineralization can lead to the hereditary form of rickets. This position paper reviews the relevant literature and presents the expertise of the Bone and Mineral Metabolism Group of the Italian Society of Pediatric Endocrinology and Diabetology (SIEDP). The aim of this document is to provide practical guidance to specialists and healthcare professionals on the main criteria for diagnosis, treatment, and management of patients with rickets. The various forms of rickets are discussed, and detailed references for the discussion of each form are provided. Algorithms to guide the diagnostic approach and recommendations to manage patients with rare forms of hereditary rickets are proposed.

The Development of Rickets in Children and Nursing Contributions to Treatment

Rickets is one of the most prevalent non-communicable diseases in children in the developing world. It is often found in cultures in which children follow strict vegetarian diets and are not exposed to vitamin D-enhanced foods. While a rare occurrence, X-linked hypophosphatemic rickets may be the most frequent type of the disease seen outside the Third World today. However, there is not much credible information on the extent of the development of rickets. Therefore, pediatric nurses must be able to recognize children at risk and provide best practice care for the prevention and treatment of rickets. When caring for children in hospitals, communities or classrooms, nurses play a vital role in identifying children at risk for hypovitaminosis D and advising families to, if possible, follow safe diets and take supplements in order to avoid health complications associated with low levels of vitamin D. This study examines the prevalence and variables contributing to rickets, including hypovitaminosis vitamin D, the consequent orthopedic problems and the role of nurses in preventing and managing the pathogenesis of rickets and ultimately avoiding extreme deficits that result in bone deformities and the need for corrective surgery.

Vitamin D, calcium or a combination of vitamin D and calcium for the treatment of nutritional rickets in children

BACKGROUND

Nutritional rickets is a disease which affects children, especially in low- and middle-income countries. It causes problems such as skeletal deformities and impaired growth. The most common cause of nutritional rickets is vitamin D deficiency. Vitamin D administered with or without calcium is commonly regarded as the mainstay of treatment. In some sunny countries, however, where children are believed to have adequate vitamin D production from exposure to ultraviolet light, but who are deficient in calcium due to low dietary intake, calcium alone has also been used in the treatment of nutritional rickets. Therefore, it is important to compare the effects of vitamin D, calcium or a combination of vitamin D and calcium for the treatment of nutritional rickets in children living in different settings.

OBJECTIVES

To assess the effects of vitamin D, calcium or a combination of vitamin D and calcium for the treatment of nutritional rickets in children.

SEARCH METHODS

We searched CENTRAL, MEDLINE, LILACS, WHO ICTRP Search Portal and ClinicalTrials.gov. The date of the last search of all databases was 25 July 2019. We applied no language restrictions.

SELECTION CRITERIA

We included randomised controlled trials (RCT) involving children aged 0 to 18 years with nutritional rickets which compared treatment with vitamin D, calcium or a combination of vitamin D and calcium.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the title and abstracts of all studies, extracted data and assessed the risk of bias of included studies. We resolved any disagreements by consensus or recourse to a third review author. We conducted meta-analyses for the outcomes reported by study authors. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (CI) and, for continuous outcomes, we calculated mean differences (MD) with 95% CIs. We assessed the certainty of the evidence of the included studies using GRADE.

MAIN RESULTS

We identified 4562 studies; of these, we included four RCTs with 286 participants. The studies compared two or more of the following: vitamin D, calcium or vitamin D plus calcium. The number of participants randomised to receive vitamin D was 64, calcium was 102 and vitamin D plus calcium was 120. Two studies were conducted in India and two were conducted in Nigeria. None of the included studies had a low risk of bias in all domains. Three studies had a high risk of bias in at least one domain. The age of the participants ranged between six months and 14 years. The duration of follow-up ranged between 12 weeks and 24 weeks. Two studies compared vitamin D to calcium. There is low-certainty evidence that, at 24 weeks' follow-up, calcium alone improved the healing of rickets compared to vitamin D alone (RR 3.26, 95% CI 1.59 to 6.69; P = 0.001; 1 study, 71 participants). Comparing vitamin D to calcium showed no firm evidence of an advantage or disadvantage in reducing morbidity (fractures) (RR 0.27, 95% CI 0.03 to 2.32; P = 0.23; 1 study, 71 participants; very low-certainty evidence). Adverse events were not reported. Two studies compared vitamin D plus calcium to vitamin D at 12 or 24 weeks. Vitamin D plus calcium improved healing of rickets compared to vitamin D alone at 24 weeks' follow-up (RR 3.06, 95% CI 1.49 to 6.29; P = 0.002; 1 study, 75 participants; low-certainty evidence). There is no conclusive evidence in favour of either intervention for reducing morbidity (fractures) (RR 0.24, 95% CI 0.03 to 2.08; P = 0.20; 1 study, 71 participants; very low-certainty evidence) or adverse events (RR 4.76, 95% CI 0.24 to 93.19; P = 0.30; 1 study, 39 participants; very low-certainty evidence). All four included studies compared vitamin D plus calcium to calcium at different follow-up times. There is no conclusive evidence on whether vitamin D plus calcium in comparison to calcium alone improved healing of rickets at 24 weeks' follow-up (RR 1.17, 95% CI 0.72 to 1.90; P = 0.53; 2 studies, 140 participants; very low-certainty evidence). Evidence is also inconclusive for morbidity (fractures) (RR 0.89, 95% CI 0.06 to 13.76; P = 0.94; 1 study, 72 participants; very low-certainty evidence) and adverse events (RR 4.29, 0.22 to 83.57; P = 0.34; 1 study, 37 participants; very low-certainty evidence). Most of the evidence in the review is low or very low certainty due to risk of bias, imprecision or both. None of the included studies assessed all-cause mortality, health-related quality of life or socioeconomic effects. One study assessed growth pattern but this was not measured at the time-point stipulated in the protocol of our review (one or more years after commencement of therapy).

AUTHORS' CONCLUSIONS

This review provides low-certainty evidence that vitamin D plus calcium or calcium alone improve healing in children with nutritional rickets compared to vitamin D alone. We are unable to make conclusions on the effects of the interventions on adverse events or morbidity (fractures).

Vitamin D insufficiency: Definition, diagnosis and management

Severe vitamin D deficiency can be defined as the dose of vitamin D or serum 25OHD concentrations needed to prevent nutritional rickets or osteomalacia. There is large international consensus that these diseases can be prevented by 400 IU of vitamin D/d and 25OHD above 30 nmol/l (12 ng/ml). Vitamin D deficiency can also accelerate the risk of fractures and probably also of falls in elderly subjects but there is no consensus on the required daily doses or minimal 25OHD threshold for these endpoints. The majority of experts consider 800 IU/d and serum 25OHD above 50 nmol/l (20 ng/ml) as sufficient, with a minority opinion aiming for 75 nmol/l or even higher. For other extra-skeletal endpoints, no hard evidence is available to define whether or not this is causally related to vitamin D status. Therefore, for these endpoints no minimal dosage or 25OHD threshold can be defined.

Transgenic Expression of the Vitamin D Receptor Restricted to the Ileum, Cecum, and Colon of Vitamin D Receptor Knockout Mice Rescues Vitamin D Receptor-Dependent Rickets

Although the intestine plays the major role in 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] action on calcium homeostasis, the mechanisms involved remain incompletely understood. The established model of 1,25(OH)2D3-regulated intestinal calcium absorption postulates a critical role for the duodenum. However, the distal intestine is where 70% to 80% of ingested calcium is absorbed. To test directly the role of 1,25(OH)2D3 and the vitamin D receptor (VDR) in the distal intestine, three independent knockout (KO)/transgenic (TG) lines expressing VDR exclusively in the ileum, cecum, and colon were generated by breeding VDR KO mice with TG mice expressing human VDR (hVDR) under the control of the 9.5-kb caudal type homeobox 2 promoter. Mice from one TG line (KO/TG3) showed low VDR expression in the distal intestine (<50% of the levels observed in KO/TG1, KO/TG2, and wild-type mice). In the KO/TG mice, hVDR was not expressed in the duodenum, jejunum, kidney, or other tissues. Growth arrest, elevated parathyroid hormone level, and hypocalcemia of the VDR KO mice were prevented in mice from KO/TG lines 1 and 2. Microcomputed tomography analysis revealed that the expression of hVDR in the distal intestine of KO/TG1 and KO/TG2 mice rescued the bone defects associated with systemic VDR deficiency, including growth plate abnormalities and altered trabecular and cortical parameters. KO/TG3 mice showed rickets, but less severely than VDR KO mice. These findings show that expression of VDR exclusively in the distal intestine can prevent abnormalities in calcium homeostasis and bone mineralization associated with systemic VDR deficiency.

[Endocrinology, what's new in 2016]

The European Society of Endocrinology has published this year a series of guidelines for hypoparathyroidism, the management of adrenal incidentalomas as well as for the long-term follow-up of patients operated on for a phaeochromocytoma/paraganglioma (PPGL). For hypoparathyroidism, guidelines insist on screening for chronic complications and monitoring treatment with calcium and vitamin D; the use of recombinant PTH may provide new opportunities for the future. Concerning adrenal incidentalomas, the panel of the guidelines primarily recommends non contrast CT for the evaluation of the risk of malignancy. Patients operated on for a PPGL, should be offered an individualized follow-up plan based on assessment of their risk of tumor recurrence.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describes the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Prevention and treatment of nutritional rickets

Nutritional rickets continues to be a significant health problem for children worldwide with recent evidence of increasing incidence in many developed countries. It is due to vitamin D deficiency and/or inadequate dietary calcium intake with variation in the relative contributions of each of these dependant on environmental factors such a dietary intake and sunlight exposure. Key to the prevention of rickets is ensuring that pregnant women and their infants receive vitamin D supplementation with good evidence from randomised controlled trials that infants who receive 400iu daily can achieve levels of 25 hydroxyvitamin D of >50nmol/l. However, public health implementation of daily supplementation is more challenging with a need to revisit food fortification strategies to ensure optimal vitamin D status of the population. Treatment of nutritional rickets has traditionally been with vitamin D2 or D3, often given as a daily oral dose for several weeks until biochemical and radiological evidence of healing. However, other treatment regimes with single or intermittent high doses have also proved to be effective. It is now recognised that oral calcium either as dietary intake or supplements should be routinely used in conjunction with vitamin D for treatment.

Global Consensus Recommendations on Prevention and Management of Nutritional Rickets

BACKGROUND

Vitamin D and calcium deficiencies are common worldwide, causing nutritional rickets and osteomalacia, which have a major impact on health, growth, and development of infants, children, and adolescents; the consequences can be lethal or can last into adulthood. The goals of this evidence-based consensus document are to provide health care professionals with guidance for prevention, diagnosis, and management of nutritional rickets and to provide policy makers with a framework to work toward its eradication.

EVIDENCE

A systematic literature search examining the definition, diagnosis, treatment, and prevention of nutritional rickets in children was conducted. Evidence-based recommendations were developed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system that describe the strength of the recommendation and the quality of supporting evidence.

PROCESS

Thirty-three nominated experts in pediatric endocrinology, pediatrics, nutrition, epidemiology, public health, and health economics evaluated the evidence on specific questions within five working groups. The consensus group, representing 11 international scientific organizations, participated in a multiday conference in May 2014 to reach a global evidence-based consensus.

RESULTS

This consensus document defines nutritional rickets and its diagnostic criteria and describes the clinical management of rickets and osteomalacia. Risk factors, particularly in mothers and infants, are ranked, and specific prevention recommendations including food fortification and supplementation are offered for both the clinical and public health contexts.

CONCLUSION

Rickets, osteomalacia, and vitamin D and calcium deficiencies are preventable global public health problems in infants, children, and adolescents. Implementation of international rickets prevention programs, including supplementation and food fortification, is urgently required.

Pathogenesis and diagnostic criteria for rickets and osteomalacia - proposal by an expert panel supported by Ministry of Health, Labour and Welfare, Japan, The Japanese Society for Bone and Mineral Research and The Japan Endocrine Society

Rickets and osteomalacia are diseases characterized by impaired mineralization of bone matrix. Recent investigations revealed that the causes for rickets and osteomalacia are quite variable. While these diseases can severely impair the quality of life of the affected patients, rickets and osteomalacia can be completely cured or at least respond to treatment when properly diagnosed and treated according to the specific causes. On the other hand, there are no standard criteria to diagnose rickets or osteomalacia nationally and internationally. Therefore, we summarize the definition and pathogenesis of rickets and osteomalacia, and propose the diagnostic criteria and a flowchart for the differential diagnosis of various causes for these diseases. We hope that these criteria and flowchart are clinically useful for the proper diagnosis and management of patients with these diseases.

A Practical Approach to Vitamin D Deficiency and Rickets

Rickets is a condition in which there is failure of the normal mineralisation (osteomalacia) of growing bone. Whilst osteomalacia may be present in adults, rickets cannot occur. It is generally caused by a lack of mineral supply, which can either occur as a result of the deficiency of calcium (calciopaenic rickets, now known as parathyroid hormone-dependent rickets) or of phosphate (phosphopaenic rickets, now called FGF23-dependent rickets). Renal disorders may also interfere with the process of mineralisation and cause rickets. Only parathyroid hormone-dependent rickets and distal renal tubular disorders will be discussed in this chapter. The most common cause of rickets is still vitamin D deficiency, which is also responsible for other problems. Disorders of vitamin D metabolism or responsiveness may also cause similar issues. Distal renal tubular acidosis may also be caused by a variety of metabolic errors similar to those of osteoclasts. One form of distal renal tubular acidosis also causes a type of osteopetrosis. This chapter describes these conditions in detail and sets out a logical approach for treatment.

Genetic rescue of glycosylation-deficient Fgf23 in the Galnt3 knockout mouse

Fibroblast growth factor 23 (FGF23) is a hormone that inhibits renal phosphate reabsorption and 1,25-dihydroxyvitamin D biosynthesis. The FGF23 subtilisin-like proprotein convertase recognition sequence ((176)RHTR(179)↓) is protected by O-glycosylation through ppGalNAc-T3 (GALNT3) activity. Thus, inactivating GALNT3 mutations render FGF23 susceptible to proteolysis, thereby reducing circulating intact hormone levels and leading to hyperphosphatemic familial tumoral calcinosis. To further delineate the role of glycosylation in the Fgf23 function, we generated an inducible FGF23 transgenic mouse expressing human mutant FGF23 (R176Q and R179Q) found in patients with autosomal dominant hypophosphatemic rickets (ADHR) and bred this animal to Galnt3 knockout mice, a model of familial tumoral calcinosis. Due to the low intact Fgf23 level, Galnt3 knockout mice with wild-type Fgf23 alleles were hyperphosphatemic. In contrast, carriers of the mutant FGF23 transgene, regardless of Galnt3 mutation status, had significantly higher serum intact FGF23, resulting in severe hypophosphatemia. Importantly, serum phosphorus and FGF23 were comparable between transgenic mice with or without normal Galnt3 alleles. To determine whether the presence of the ADHR mutation could improve biochemical and skeletal abnormalities in Galnt3-null mice, these mice were also mated to Fgf23 knock-in mice, carrying heterozygous or homozygous R176Q ADHR Fgf23 mutations. The knock-in mice with functional Galnt3 had normal Fgf23 but were slightly hypophosphatemic. The stabilized Fgf23 ADHR allele reversed the Galnt3-null phenotype and normalized total Fgf23, serum phosphorus, and bone Fgf23 mRNA. However, the skeletal phenotype was unaffected. In summary, these data demonstrate that O-glycosylation by ppGaINAc-T3 is only necessary for proper secretion of intact Fgf23 and, once secreted, does not affect Fgf23 function. Furthermore, the more stable Fgf23 ADHR mutant protein could normalize serum phosphorus in Galnt3 knockout mice.

Rickets

Rickets, historically referred to as "the English disease", is common worldwide. Absence of phosphate at the growth plate and mineralising bone surfaces due to inadequate vitamin D supply either from sunlight exposure or diet is the main cause. Inherited disorders causing hypophosphataemia have shown the intricacies of phosphate metabolism. Present advice about the provision of vitamin D to young infants needs to be clarified; the existing guidance is fragmentary and contradictory, and will not help to eradicate the disease.

[Osteoporosis]

The quality of the management of patients with osteoporosis varies by country. The recommendations of the Swiss Association against osteoporosis propose intervention thresholds based on the results of the FRAX tool. Despite increasing number of observational studies with several hundred thousands of patients, it is not possible to conclude to a clear increased risk of cardiovascular disease with calcium intakes. A persistent effect of zoledronic acid is observed even after one single injection. There is no increased fracture risk within 7 months following Denosumab treatment cessation.

RICKETS IN RURAL KENYAN PRESCHOOL CHILDREN: CASE REPORT

Clinical rickets has not been reported previously in Embu district, Kenya. Baseline clinical assessments performed for a nutrition intervention study in preschool children (n=324) identified 28 cases of rickets (8.6% of study sample). Clinical characteristics included: delays of sitting, walking, and teething; bone and chest deformities; widened wrists and ankles; and bowed lower extremities. Risk factors identified were short duration of breastfeeding with feeding of cereal-based supplements with little or no milk, low calcium intake, limited sunlight exposure. Vitamin D and calcium deficiencies likely contributed to these cases. Treatment with Vitamin D3 and milk resulted in clinical improvement.

Regulation of bone-renal mineral and energy metabolism: the PHEX, FGF23, DMP1, MEPE ASARM pathway

More than 300 million years ago, vertebrates emerged from the vast oceans to conquer gravity and the dry land. With this transition, new adaptations occurred that included ingenious changes in reproduction, waste secretion, and bone physiology. One new innovation, the egg shell, contained an ancestral protein (ovocleidin-116) that likely first appeared with the dinosaurs and was preserved through the theropod lineage in modern birds and reptiles. Ovocleidin-116 is an avian homolog of matrix extracellular phosphoglycoprotein (MEPE) and belongs to a group of proteins called short integrin-binding ligand-interacting glycoproteins (SIBLINGs). These proteins are all localized to a defined region on chromosome 5q in mice and chromosome 4q in humans. A unifying feature of SIBLING proteins is an acidic serine aspartate-rich MEPE-associated motif (ASARM). Recent research has shown that the ASARM motif and the released ASARM peptide have regulatory roles in mineralization (bone and teeth), phosphate regulation, vascularization, soft-tissue calcification, osteoclastogenesis, mechanotransduction, and fat energy metabolism. The MEPE ASARM motif and peptide are physiological substrates for PHEX, a zinc metalloendopeptidase. Defects in PHEX are responsible for X-linked hypophosphatemic rickets (HYP). There is evidence that PHEX interacts with another ASARM motif containing SIBLING protein, dentin matrix protein-1 (DMP1). DMP1 mutations cause bone and renal defects that are identical with the defects caused by a loss of PHEX function. This results in autosomal recessive hypophosphatemic rickets (ARHR). In both HYP and ARHR, increased FGF23 expression plays a major role in the disease and in autosomal dominant hypophosphatemic rickets (ADHR), FGF23 half-life is increased by activating mutations. ASARM peptide administration in vitro and in vivo also induces increased FGF23 expression. FGF23 is a member of the fibroblast growth factor (FGF) family of cytokines, which surfaced 500 million years ago with the boney fish (i.e., teleosts) that do not contain SIBLING proteins. In terrestrial vertebrates, FGF23, like SIBLING proteins, is expressed in the osteocyte. The boney fish, however, are an-osteocytic, so a physiological bone-renal link with FGF23 and the SIBLINGs was cemented when life ventured from the oceans to the land during the Triassic period, approximately 300 million years ago. This link has been revealed by recent research that indicates a competitive displacement of a PHEX-DMP1 interaction by an ASARM peptide that leads to increased FGF23 expression. This review discusses the new discoveries that reveal a novel PHEX, DMP1, MEPE, ASARM peptide, and FGF23 bone-renal pathway. This pathway impacts not only bone formation, bone-renal mineralization, and renal phosphate homeostasis but also energy metabolism. The study of this new pathway is relevant for developing therapies for several diseases: bone-teeth mineral loss disorders, renal osteodystrophy, chronic kidney disease and bone mineralization disorders (CKD-MBD), end-stage renal diseases, ectopic arterial-calcification, cardiovascular disease renal calcification, diabetes, and obesity.

[Laboratories "Produits Scientia" and mineral waters from Pougues and Carabana]

In the end of XIXth century, the french "Compagnie des eaux minérales de Pougues-les-Eaux" begins to exploit the spanish natural purgativ water of Carabaña. In the same way, Edouard Jéramec, director of the french compagny, decides to associate to his firm the best medicine to fight against rickets and tuberculosis. He joins the new medical theory wich recommends to give more calcium to tubercular patients, called "méthode de recalcification du Dr Ferrier". Then, with the chemist Emile Perraudin, he creates the pharmaceutical laboratory named "Produits Scientia". One of their famous patents medicines will be the "Tricalcine".

The role of vitamin D in paediatric bone health

Recently there has been renewed interest in the role of vitamin D in paediatric bone health. Its role in the development of rickets and hypocalcaemia in infants and young children, in particular, in many part of the world is well known, and the importance of the prevention of vitamin D deficiency during pregnancy and lactation has been highlighted. Less clear are the possible effects that maintaining maternal vitamin D sufficiency might have on foetal and early infant growth and bone development. There is little evidence to suggest that maintaining childhood vitamin D status well above that necessary to prevent rickets has an effect on intestinal calcium absorption or on peak bone mass. Further studies are needed in these areas prior to definitive conclusions are drawn about the optimal vitamin D requirements and circulating 25(OH)D concentrations for foetal, infant and childhood bone health.

Evaluation of children with nutritional rickets

AIM

To evaluate the clinical findings, risk factors, therapy and outcome in 946 children with nutritional rickets.

PATIENTS AND METHODS

This retrospective study included a review of medical records of patients with nutritional rickets between March 2004 and 2009. Patients who displayed both the biochemical inclusion criteria and the clinical signs/symptoms or radiological signs of rickets were included in the study.

RESULTS

The present study included 946 patients aged between 4 months and 15 years. Distribution of the cases showed a density between December and May. The age at diagnosis, showed two peaks and most of the patients were in the age range 0-23 months and 12.0-15 years. In infants and young children, most of the patients had been admitted to the hospital due to infectious diseases. In older children, short stature and obesity were the most common complaints.

CONCLUSION

Children aged between 0-23 months and 12.0-15 years were under most risk for nutritional rickets, especially in winter and spring and vitamin D should be given to them as supplementation dose.

Nutritional deficiencies during normal growth

Nutritional deficiencies have always been a major consideration in pediatrics. Although the classic forms of many of the well-documented nutritional deficiencies are memorized during training as a physician, nutritional deficiencies that can occur in otherwise asymptomatic normally growing children are often overlooked. The two most common deficiencies seen in children who are growing normally are iron and vitamin D deficiencies. These deficiencies are surprisingly common and can have a significant impact on the overall health of a child. This article reviews these nutritional deficiencies and other less commonly seen deficiencies in children who are otherwise growing normally.

A practical approach to rickets

Rickets is a condition in which there is failure of normal mineralisation (osteomalacia) of growing bone. Whilst osteomalacia may be present in adults, rickets cannot occur. It is generally caused by a lack of mineral supply which can either be as a result of deficiency of calcium (calciopaenic rickets) or of phosphate (phosphopaenic rickets) although, in addition, renal tubular acidosis may also interfere with the process of mineralisation and cause rickets. Only calciopaenic and distal renal tubular disorders will be discussed in this chapter. The commonest cause of rickets is still vitamin D deficiency which is also responsible for problems other than rickets. Disorders of vitamin D metabolism or responsiveness may also cause similar problems. Distal renal tubular acidosis may be caused by a variety of metabolic errors similar to those of osteoclasts. One form of DRTA also causes a form of osteopetrosis. This chapter describes these conditions in detail and sets out a logical approach to treatment.

[Omega-3: from cod-liver oil to nutrigenomics]

The leading role of cod-liver oil on rickets was a relevant factor in the knowledge of this disease. In 1922 the preventive and therapeutic value of cod-liver oil and sunlight against rickets in young infants was confirmed. The seasonal variation in the incidence of rickets, the role of skin pigmentation, of diet and the fact that breast milk was not an adequate source of vitamin D were understood. The discovery of essential fatty acids omega-6 and omega-3 have shown that deficiencies, mainly of omega-3 long chain polyunsaturated fatty acids, result in visual and cognitive impairment and disturbances in mental functions in infants and also in cognitive function in adults, as fatty acids are beneficial to vascular health and may forestall cerebrovascular disease and thus dementia. An adequate ratio of n-6 and n-3 fatty acids may promote a healthier balance of eicosanoids, which would protect membrane function with a nutraceutical function. Dietary lipids not only influence the biophysical state of the cell membranes but, via direct and indirect routes, they also act on multiple pathways including signalling, gene and protein activities, protein modifications and they probably play important role in modulating protein aggregation. Significant advances have been made in understanding the relation between dietary factors and inflammation, which is a central component of many chronic diseases, including coronary artery disease, rheumatoid arthritis, cancer prevention. However, the identification of those who will or will not benefit from dietary intervention strategies remains a major obstacle. Adequate knowledge about how the responses depend on an individual's genetic background (nutrigenetic effects), the cumulative effects of food components on genetic expression profiles through nutrigenomics mechanism, may assist in identifying responders and non-responders. Thus, fish and fish oil consumption might encourage brain development and gene expression to brain maintenance during aging through nutrigenomic mechanism.

Vitamin D deficiency in exclusively breast-fed infants

Exclusive breast-feeding is recommended up to 6 months of age with all its beneficial effects on child survival. Several studies have concluded that adequate intake of vitamin D cannot be met with human milk as the sole source of vitamin D. As breast-feeding rates increase, the incidence of vitamin D deficiency rickets is also expected to rise. One of the potential sources of vitamin D synthesis is in the skin from the ultraviolet rays of sunlight. Risk factors for developing vitamin D deficiency and rickets include low maternal levels of vitamin D, indoor confinement during the day, living at higher altitudes, living in urban areas with tall buildings, air pollution, darker skin pigmentation, use of sunscreen and covering much or all of the body when outside. In a study of 50 cases of hypocalcaemia reported from an urban tertiary care children's hospital in Chennai, 13 exclusively breast-fed infants presented with hypocalcaemia due to vitamin D deficiency and most of them with seizures. None of them had received vitamin D supplementation and all their mothers had biochemical evidence for vitamin D deficiency. This review discusses the rising incidence of vitamin D deficiency in infancy and the need to consider and implement methods to prevent the same by supplementation and increased exposure to sunlight without the hazards of ultraviolet rays on the skin. Further research to define the magnitude of vitamin D deficiency in exclusively breast-fed infants as a public health and paediatric problem and to recommend programmes to prevent the same are of utmost importance.

Severe bilateral rachitic genu valgum in patients with nonbullous congenital ichthyosiform erythroderma: a report of two cases and review of literature

We present two cases of ichthyosiform erythroderma associated with severe bilateral genu valgum. Other musculoskeletal features associated with this condition are described. The details and outcome of operative intervention for the correction of the deformities are discussed. The disturbances of the metabolism of vitamin D and medical management are discussed. A review of literature is presented.

[Brief history of rickets and of the discovery of vitamin D]

Almost eighteen centuries mediated between the first cases of rickets, reported by Soranus and Galeno, and the clarification of the disease aetiology. Due to the outbreak of rickets verified in the 17th century in England, the situation was known as the 'English disease', being its first detailed description presented by Francis Glisson. The growing incidence of rickets with the Industrial Revolution raised speculations about its origin and treatment. The characterization of solar light and luminous spectrum led to the identification of the biological effects of ultraviolet radiation, and to the discovery of phototherapy as an alternative therapeutic process to the solar irradiation. The experimental rickets achieved by Mellanby and McCollum gave support to the concept that this situation could have an origin in a dietary defect. It was also referred an inverse relationship between sun exposure and the incidence of rickets. The identification of the chemical nature of an essential dietary factor with anti-rickets effect (ergocalciferol or vitamin D2), together with another factor with identical properties, but more potent, produced in the skin exposed to sunlight (cholecalciferol or vitamin D3), was essential to the elucidation, prevention and therapy of the disease. The present revision summarizes the history of rickets, the characterization and anti-rickets properties of the light and dietary supplements of lipid nature, and the identification of the major biological forms of vitamin D.

Metabolic bone disease in adolescents: recognition, evaluation, treatment, and prevention

Bone is a metabolically active organ that undergoes constant remodeling. Bone is very important for maintaining homeostasis of calcium and phosphorous in the body. Disorders of bone metabolism may encompass disease processes involving underactive or overactive bone turnover. The spectrum of abnormal bone metabolism includes rickets and osteomalacia; osteopenia and osteoporosis; osteogenesis imperfecta, renal osteodystrophy; osteopetrosis and osteosclerosis; and effect of pharmacologic therapies on bone metabolism. The recognition, evaluation, treatment, and prevention of these conditions will be discussed after a brief description of normal bone metabolism.

Scurvy and rickets masked by chronic neurologic illness: revisiting "psychologic malnutrition"

The North American epidemic of overeating, combined with a sedentary lifestyle, has led to a growing prevalence of obesity, diabetes, and the "metabolic syndrome" in children. Excessive caloric intake does not imply adequate nutrition, and vitamin-deficiency syndromes still occur in some American children. Here we describe cases of scurvy and vitamin D deficiency in 2 children with cognitive disorders. Thorough dietary histories suggested the diagnosis in each patient and, had they been obtained at presentation, would likely have obviated invasive diagnostic workup, unnecessary stress to the patients and their families, and significant functional disability. Overnutrition and malnutrition may coexist, particularly among those with abnormal cognition or autistic spectrum disorders. Classic nutritional deficiencies must not be omitted from the differential diagnosis. A comprehensive dietary history and screening for vitamin deficiencies in at-risk children are important aspects of preventive health care and are essential for prompt diagnosis and treatment.

Rickets in the 17th century

Rickets was first documented as a cause of death in the Bills of Mortality for The City of London in 1634, but detailed descriptions were only published between 1645 and 1668. It was thought at the time that this was a new disease in England, but there was no indication as to the cause of the condition. However, air pollution from smoke produced by burning coal caused serious problems at that time, and so it can be suggested that vitamin D deficiency was responsible.

Rickets: not a disease of the past

Rickets develops when growing bones fail to mineralize. In most cases, the diagnosis is established with a thorough history and physical examination and confirmed by laboratory evaluation. Nutritional rickets can be caused by inadequate intake of nutrients (vitamin D in particular); however, it is not uncommon in dark-skinned children who have limited sun exposure and in infants who are breastfed exclusively. Vitamin D-dependent rickets, type I results from abnormalities in the gene coding for 25(OH)D3-1-alpha-hydroxylase, and type II results from defective vitamin D receptors. The vitamin D-resistant types are familial hypophosphatemic rickets and hereditary hypophosphatemic rickets with hypercalciuria. Other causes of rickets include renal disease, medications, and malabsorption syndromes. Nutritional rickets is treated by replacing the deficient nutrient. Mothers who breastfeed exclusively need to be informed of the recommendation to give their infants vitamin D supplements beginning in the first two months of life to prevent nutritional rickets. Vitamin D-dependent rickets, type I is treated with vitamin D; management of type II is more challenging. Familial hypophosphatemic rickets is treated with phosphorus and vitamin D, whereas hereditary hypophosphatemic rickets with hypercalciuria is treated with phosphorus alone. Families with inherited rickets may seek genetic counseling. The aim of early diagnosis and treatment is to resolve biochemical derangements and prevent complications such as severe deformities that may require surgical intervention.

Evaluation of stature development during childhood and adolescence in individuals with familial hypophosphatemic rickets

This review was conducted to study the diagnosis, treatment, and growth progression in infants and adolescents with familial hypophosphatemic rickets. The bibliographic search was carried out utilizing the electronic databases MEDLINE, OVID, and LILACS and by direct research within the last 15 years using the keywords rickets, familial hypophosphatemia, vitamin D deficiency, stature growth, childhood, and adolescence. Article selection was done by comparing the evaluation of the growth in patients with familial hypophosphatemic rickets, including the variables that might affect them, for possible future therapeutic proposals. It is concluded that the most significant fact in the treatment of familial hypophosphatemic rickets in infancy was the magnitude of the final stature. The use of growth hormone can be helpful in these patients. However, research reporting treatments with the use of the growth hormone for rickets are controversial. The majority of the authors agree that treatment using vitamin D and phosphate enables some statural growth in cases of early diagnosis, reflecting a better prognosis.

Rickets in an adolescent girl

The authors present a case of rickets in an adolescent girl who presented to the emergency department with bone pain. Emergency department staff should be aware that rickets is not just a disease of early childhood.

Respiratory distress: a rare presentation of rickets

Nutritional rickets has multiple presentations like skeletal deformities, tetany, hypocalcemic seizures, recurrent diarrhea, dental abnormalities, developmental delay and floppiness. Here a rare presentation of nutritional rickets is reported in five months old baby who had respiratory distress since two months and signs of respiratory distress resolved after start of vitamin-D supplementation.

Sir Robert Hutchison (1871-1960) of London and the causes and treatment of rickets

A general physician with a special interest in nutrition and in children, Sir Robert Hutchison became a leader in medicine and paediatrics in the United Kingdom during the early decades of the 20th century. His wisdom and wit educated and amused successive generations of students and doctors.

Rickets and vitamin D deficiency in children and adolescents

This article discusses the pathogenesis, epidemiology, prevention, and treatment of nutritional rickets in children, highlighting the roles of exclusive breastfeeding and low dietary calcium intakes in its pathogenesis. The worldwide nature of the problem is described. Preventive strategies are discussed, and various treatment options are provided.

Diagnostik und Therapie der Rachitis

Rickets is caused by deficient mineralization at the level of growth plate and is usually due to a decreased serum calcium/phosphate product. Although the diagnosis of rickets can usually be suspected on the basis of a clinical examination (bone deformities in legs, impaired growth), radiological examination and detailed biochemical work-up are necessary to elucidate the etiology of the underlying disease. It is important to differentiate between calcipenic/vitamin deficient and phosphopenic rickets. The former is due to vitamin D deficiency, and the ultimate cause of this usually lies in altered vitamin D supply; however, impaired synthesis of or resistance to the actions of vitamin D can also be a cause. Phosphopenic rickets is usually related to impaired phosphate reabsorption in the proximal renal tubule. Both calcipenic and phosphopenic rickets can be acquired or hereditary in origin.